This invention relates to improved apparatus suitable for stent delivery and implantation.
Stents are implantable devices which are placed within body lumens and the like, such as blood vessels. Stents are typically tubular in form, the diameter of which can be increased for implantation. They maybe made of plastic or metal. Stents are usually introduced for implantation percutaneously by means of a catheter and the diameter of the stent is increased by inflation of a balloon on the catheter.
In one aspect, this invention relates to an improvement in the stent delivery system described in U.S. Pat. No. 4,950,227 to Savin et al., entitled xe2x80x9cStent Delivery Systemxe2x80x9d and issued on Aug. 21, 1990. This patent is incorporated herein in its entirety by reference.
That patent discloses a stent delivery system in which a catheter carries, on its distal end portion, a stent which is held in place around the catheter prior to and during percutaneous delivery by means of one and preferably two sleeves. The sleeves are positioned around the catheter with one end portion attached thereto and overlap an end portion(s) of the stent to hold it in place on the catheter in a contracted condition. Each sleeve is elastomeric in nature so as to stretch and release the stent when it expands for implantation. The stent is expandable by means of the expandable balloon on the catheter.
In a first aspect, this invention provides securement of a stent on a balloon by means of a folded or rolled end portion of the balloon itself.
In another aspect of this invention the balloon configured as described above is used in combination with the elastic sleeves of the Savin et al. patent.
Additionally, the balloon shape may be modified, as by enlarged cone portions, to facilitate the above improvements.
Moreover, these features may be used alone or in combination and may be applied to one or both ends of the stent to secure it for delivery.